title: Lead(II) resistance in Cupriavidus metallidurans CH34: interplay between plasmid and chromosomally-located functions.
abstract: Proteome and transcriptome analysis, combined with mutagenesis, were used to better understand the response of Cupriavidus metallidurans CH34 against lead(II). Structural Pb(II)-resistance genes of the pMOL30-encoded pbrUTRABCD operon formed the major line of defense against Pb(II). However, several general stress response mechanisms under the control of alternative sigma factors such as sigma24/rpoK, sigma32/rpoH and sigma28/fliA were also induced. In addition, the expression of the pbrR(2) cadA pbrC(2) operon of the CMGI-1 region and the chromosomally encoded zntA were clearly induced in the presence of Pb(II), although their respective gene products were not detected via proteomics. After inactivation of the pbrA, pbrB or pbrD genes, the expression of the pbrR(2) cadA pbrC(2) operon went up considerably. This points towards synergistic interactions between pbrUTRABCD and pbrR(2) cadA pbrC(2) to maintain a low intracellular Pb(II) concentration, where pbrR(2) cadA pbrC(2) gene functions can complement and compensate for the mutations in the pbrA and pbrD genes. This role of zntA and cadA to complement for the loss of pbrA was further confirmed by mutation analysis. The pbrB:: colonsTn(Km2) mutation resulted in the most significant decrease of Pb(II) resistance, indicating that Pb(II) sequestration, avoiding re-entry of this toxic metal ion, forms a critical step in the pbr-encoded Pb(II) resistance mechanism.
authors.affiliation: Biology Department, Brookhaven National Laboratory, Building 463, Upton, NY 11973-5000, USA.
authors.forename: Safiyh
authors.initials: S
authors.lastname: Taghavi
authors.forename: Celine
authors.initials: C
authors.lastname: Lesaulnier
authors.forename: Sebastien
authors.initials: S
authors.lastname: Monchy
authors.forename: Ruddy
authors.initials: R
authors.lastname: Wattiez
authors.forename: Max
authors.initials: M
authors.lastname: Mergeay
authors.forename: Daniel
authors.initials: D
authors.lastname: van der Lelie
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002876:Chromosomes, Bacterial / Q000235:genetics*; D049921:Cupriavidus / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D005296:Ferrous Compounds / Q000378:metabolism / Q000494:pharmacology*; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D007854:Lead / Q000378:metabolism / Q000494:pharmacology*; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D009876:Operon; D010957:Plasmids / Q000235:genetics*; D020543:Proteome; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D001426:Bacterial Proteins; D005296:Ferrous Compounds; D020543:Proteome; D007854:Lead; D000251:Adenosine Triphosphatases; C436314:PbrA protein, Ralstonia metallidurans